The goal of the proposed project is to combine the efforts of seven investigators in the study of several facets of the endocrinology of aging. These studies will be carried out in man and rat. Areas to be investigated will include the effects of age on: steroid binding and action in control of calcium metabolism; reproductive endocrinology, somatomedin and somatomedin responsiveness; neuroendocrine responses; calcitonin, PTH and Vitamin D concentration and action; glucose tolerance; and hemoglobin glycosylation.